This invention relates to locking mechanisms for head/arm mechanisms of a disk drive.
In disk drives of the class wherein the head "lands" on the disk surface, it is important to employ a mechanism to lock the head in a retracted position to prevent damage to the drive during transportation and other times of nonuse. Heretofore, lock mechanisms for disk drives have operated under either of two principles. One class employs fully mechanical devices, usually operated manually by a lever or the like, which engage the arm to lock it in a retracted position. The second class employs solenoids which are usually energized in one or the other position to lock or unlock the head/arm assembly. One difficulty with the mechanical leverage locks is that the moving parts often scraped against each other, dislodging particles from the parts which contaminated the drive and media. The particles interfered with the operation of the disk drive and the flying characteristics of the head. The solenoid locks required energization to maintain the head/arm assembly in either a locked or unlocked position. The constant energization of the mechanism generated heat within the disk drive, causing yet other problems. (There is a third type of lock mechanism employing mechanical locks operated by solenoids. In reality, these "hybrid" mechanisms exhibit the adverse characteristics of both the mechanical and solenoid mechanisms by requiring constant energization in one or the other positions and by mechanical scrapping of the parts.)
Examples of these systems can be found in U.S. Pat. Nos. 4,583,142 (mechanical), 4,139,874 (solenoid) and 4,392,165 (hybrid).